"Fells" translates to hills or moorland, thus "troll-fells" were hills in which trolls lived.[8]

The first instance of troll-fells was devoid of a dash and was capitalized, "Trollfells": J.R.R. Tolkien wrote on a map: "Alter Entish Lands to [Trollfells > Bergrisland >] Ettenmoor". This is also the first mention of Ettenmoor(s) in the legendarium.[9]

The Ettenmoors is the region where player vs player play takes place. The land has three keeps (Lugazag, Tirith Rhaw and Tol Ascarnen), Isendeep Mine and Grimwood Lumber Camp that can be controlled by either the forces of Angmar or the Free Peoples of Middle-earth.